How do I read the flash distance scale on the Canon 580EX II?

Question

My Canon 580EX II has a distance scale running from 0.5m to 18m.

When the flash is in manual mode, a single segment of the distance scale illuminates to indicate the maximum effective range for my current aperture and ISO settings.

In E-TTL II mode, the scale illuminates a number of segments. For example, if I set my aperture to f5.6 and ISO to 400, 7 segments illuminate between 1m and 9m. What does this mean?

Asked by gjb

Answer

This shows you the optimum range of distances you can use those settings with. In your example, beyond 9m and the camera settings mean you won't be able to illuminate the subject properly; and closer than 1m and the subject will be overexposed even on the flash's minimum setting.

In manual mode, you've already determined the flash power, so the effective range is reduced to just the single bar.

Answered by Nick Miners

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